package jxc.base.helper;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
/**
 * 包含一些静态加密函数的类,不过实际上,截至目前,只有一个函数 MD5
 * @author wenjianwzz
 * @version 0.5
 */
public class Encrypt {

	/**
	 * MD5加密,如果plainText==null,return null
	 * @param plainText
	 * @return MD5加密后的字符串
	 */
	static public String md5(String plainText) {
		if(plainText==null)
			return null;
		try {
			MessageDigest md = MessageDigest.getInstance("MD5");
			md.update(plainText.getBytes());
			byte b[] = md.digest();
			int i;
			StringBuffer buf = new StringBuffer("");
			for (int offset = 0; offset < b.length; offset++) {
				i = b[offset];
				if (i < 0)
					i += 256;
				if (i < 16)
					buf.append("0");
				buf.append(Integer.toHexString(i));
			}
			return buf.toString();
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
			return null;
		}
	}
}
